


Perfect Comprehension

by iridescentAI



Series: The Space Between [1]
Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe - Canon Divergence, F/M, Female My Unit | Byleth, M/M, Multi, Pining, Post-Timeskip | War Phase (Fire Emblem: Three Houses), Sylvain has a lot of feelings, felix can't acknowledge the fact that he has feelings beyond rage, it's post-timeskip but everyone is here, technically this is an AU, where is Sylvain's self worth
Language: English
Status: Completed
Published: 2019-09-18
Updated: 2019-09-22
Packaged: 2020-11-02 08:20:30
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 8,805
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20681675
Author URL: https://archiveofourown.org/users/iridescentAI/pseuds/iridescentAI
Summary: Pretty much everyone at Garreg Mach is at least a little bit in love with Byleth. Not everybody can admit it.





	1. Felix

**Author's Note:**

> Guess whose roommate got them into a new hyperfixation.

There's something about this odd feeling in his chest that Felix can't shake. 

He'd thought he'd gotten rid of it at the academy, five years ago -- back when everything was simple, back when everyone was friends. Back then, he'd squashed down everything that wasn't determination and rage without remorse.

Something about the past five years has fucked with him. Maybe it's the steady stream of losses on both sides, friend and foe alike. Maybe it's that everything he knows keeps getting flipped on its head. He's not really sure -- and he doesn't really care about the specifics. 

But he can't seem to squash down that _feeling_ anymore. 

It's this pang in his chest, a physical pain he can't explain, it's his stomach twisted up in knots, like the feeling he gets when an ally gets hurt and falls behind, it's this tingling feeling in his hands, as if he's itching to hold something.

Usually, he just tightens his grip on his sword and keeps training. He tries not to puzzle over it. 

\---

The realization hits him on the training grounds -- which isn't surprising, considering how often he's there.

He spends most of his time sparring with whoever will agree to the challenge and practicing on stuffed dummies when no one’s available. He’s even spent a few nights here, his coat draped over his body in place of a blanket. 

It begins when Byleth stops in right before lunch. 

As much as Felix tries to convince himself he doesn’t care about anything but training, he still tracks her movements across the room. 

(Which is why he doesn't jump right out of his skin when she appears in his peripherals, as silent and expressionless as always, no footsteps or shuffling of clothes to speak for her movements or announce her approach.)

Byleth watches him practice, and Felix tries to ignore the weight of those green eyes where they rest on him. He ignores her, ignores the thrumming of his heart.

He's just. Excited. That's all. Just excited to be in the vicinity of a worthy opponent.

When he finally finishes his last set, his old professor steps forwards, replacing the weight of her eyes with the press of her hand. 

She could’ve just as easily called his name to catch his attention, but instead, she presses into his shoulder -- and he should _not_ be so excited by the strength behind the push of that palm, by the brush of fingers against his collarbone --

“What do you want,” Felix grinds out, gripping the hilt of his sword ever tighter. Surely, if he lets go, it will be obvious that he’s trembling. <strike>Tired, he's just tired.</strike> “Can’t you see I’m busy?”

Somehow, his abrasive remarks bring a smile to his teacher’s face -- and _fuck_, he’s not _used_ to her smiling, not used to the way her eyes light up, the way her lips curl,

“Spar with me?” Byleth offers, raising a training sword into his line of sight. 

Felix scowls and scoffs, as if the proposition doesn’t send a thrill through his body. “If you really think you can win.” He tosses his head, gesturing to a box marked out on the ground nearby, indicating the arena they should compete within. 

He's just anticipating sparring with a worthy opponent, that's all. 

He stands across from her, readying his sword in front of him with all of the determination in the world. The longer he looks at her stance, at the fire, the determination in her eyes, the more his own competitive nature rears its head, overtaking the trembling in his arms and steadying his blade. 

When she shoots forwards, engaging him first, Felix is ready. 

He can do this. This is his comfort zone. This is what he knows best. 

There's nothing to trip him up here -- not even how incredibly attractive his professor looks while she's attempting to kill him.

_Oh fuck- is_ that _what this is?!_

And, shame on him, he freezes.

The moment he lets his guard down, Byleth yells a triumphant _hyah!_ and wacks him clean across the face. He doesn't even lift a finger to deflect the blow.

If that wasn't victory enough, Felix drops his sword and stumbles back, eyes wide and staring at absolutely nothing. He can't react, he's frozen like the winters of Farghus. He can't even be bothered to press a hand to his throbbing cheek.

_ Am I really attracted to- is this really- _

_ For the professor? _

It all comes as a surprise to him, an avalanche of realization. 

He's been attracted to people before, but the feeling was always fleeting. He mostly disregards other people -- he's too good a judge of character. The first meeting with someone usually tells him all he needed to know. He's already cataloged who's a threat and who's not, which allows him to divert the maximum amount of attention into training_._

The only way to catch his attention was to surprise him. (He specifically remembers a rather disarming incident with Bernadetta, all those years ago…)

Once someone caught his attention, one or two things needed to happen for them to _keep_ it.

They had to step up and prove themselves to him, or, in cases where he was the more invested party, he pursued them until he figured them out.

People are like puzzles. The more interesting ones take a moment for Felix to unravel, but he always figures them out in the end. 

Which is why this feeling, _this_ particular feeling, is _new_ for him. 

Byleth has proved herself to him over and over again. That's not the problem.

_ Felix cannot figure her out. _

He can't find the pattern to her actions, he can't always match the emotion to her expression, and when he snaps and strikes with what he thinks will push her buttons, she never reacts like he expects her to. 

Like now, when she cries out and rushes forwards with concern, Felix regains himself and waves her off. He's expecting her to be relieved that he's alright, because he's clearly just fine, but her eyebrow twitches in something like irritation, and she steps closer to fuss over him instead.

Byleth rarely "fusses," but he supposes he's warranted some concern, considering he's one of the best (if not _the_ best) swordsman here and he just _watched_ while an opponent smacked him in the face.

He lets her fingers dance over his cheek, makes sure to complain when he feels the familiar tingle of white magic, and stands still while she turns his face back and forth in her hands. His face is full of contempt and irritation, eyebrows drawn and lips pulled down in a frown, but his heart thunders in his ears and his chest is tight with that _feeling_.

"I healed the bruise, but," Byleth murmurs, still inspecting him. "I think you have a concussion."

His professor has only just recently picked up white magic, so she's not quite skilled enough to help with anything beyond cuts and bruises. 

Felix knows that denying the diagnosis just so he can go back to training will not fly with her. And, for once, he predicts correctly. When he attempts to pick up his sword to totter back to the training dummies, she marches after him with something that looks distinctly like determination in her eyes.

And it's a good thing she does come after him, because, as he attempts to retrieve his sword off the ground, he discovers he may very well indeed have a concussion.

The world unceremoniously tilts _way_ too far, and Felix is falling before he can register where the ground is.

Luckily, he never lands.

Unluckily, he falls headlong into a warm, study body.

Byleth cradles his head against her chest, her knees in the dirt while she steadies him. The line of his body settles into hers with every passing moment -- as if he _belongs_ here, or something.

When he feels his stomach flip, feels his abs clench, he prays to the goddess that he won't pop a boner right here and now.

"Let me take you to the infirmary." 

It's both a request and a command, making sure Felix knows _exactly_ what she expects of him, yet leaving room for him to continue being stubborn, if he so wishes. 

And he _does_ so wish to continue being stubborn, but when her fingers slip into his hair, carding through what little she can without pulling his ponytail out, he's a lost cause.

"Fine." His assent is coerced from him after another scrape of her fingernails. "If you really think it's necessary."

Which is how he finds himself propped against his old professor, leaning heavily on her shoulders while she helps him cross the grounds of Garreg Mach.

He remembers, by no choice of his own, how popular Byleth is. Everyone stops Byleth for a word or two -- knights, students, teachers, and townspeople alike, as if she's not carrying a student to the infirmary. 

It comforts him to know that he's not the only one that still calls her "professor," despite the fact that they’re in the middle of a war and none of them are students anymore. 

As the two of them approach the stairs, he catches Ingrid’s gaze. She raises an eyebrow at his predicament, intrigued, and Felix scowls, baring his teeth at her as they pass by. Ingrid rolls her eyes, unimpressed and all too used to his standoffish behavior, but she does smile and wave to Byleth. 

“Oh, hey Teach!” Claude appears out of nowhere, smile all too bright, green eyes sparkling the way they only do around the professor. “Can I run something by you real quick?”

The Alliance leader hides all of his serious emotions under jokes and sly smiles, so, on a surface level, it seems that Claude just really trusts and admires Byleth.

But Felix _knows_ better. He, too, knows how to mask his true feelings with something else, something that’s an integral part of his personality but he really doesn’t mean. Recognizing it in other people is not difficult for him. Recognizing the stronger emotions hidden behind Claude's mask is not difficult for him.

Felix does not like Claude. 

While Byleth nods along to Claude’s explanation of his latest scheme, Felix watches Claude’s guard go down, watches the hard edge of his emerald gaze soften into something warm and sweet. 

When Felix tips a little too far to the side, startling Claude and sending Byleth into a flurry of readjustments to keep him comfortably slung across her shoulders, it may or may not have been on purpose. 

“We’ll catch up later, Teach,” Claude decides, flashing their old professor a wink. “Hang in there, Felix!” He calls before he wanders off, waving pleasantly, smiling pleasantly, _existing_ pleasantly,

Byleth adjusts her grip again and murmurs an apology for getting sidetracked, but suddenly, Felix is too focused on her newfound grip on his waist to answer. 

They make it to the stairwell before they get interrupted again. 

“Professor!” It’s Edelgard, this time, and Felix nearly groans out loud. “Have you seen Claude? We were discussing the power structure of Eastern Fodlan, but he disappeared all of a sudden,” she muses, brow furrowed with frustration. 

Wordlessly, Byleth points her in the right direction, and Edelguard’s earnest _thank you so much_ is maybe a little too earnest for such a small favor. Before she chases after Claude, the former house leader pauses, gazing fondly at their professor (as if Felix isn’t even there), and assures her they’ll have dinner together later. 

Edelgard is a different breed than Felix and Claude. 

She doesn’t hide anything, all of her true feelings on display for all to see -- especially when it comes to the professor. If she wants to avoid discussing something in detail, she doesn’t change her act, she changes the subject -- probably fully aware that everyone can tell when she’s lying. 

It is _quite_ obvious -- it’s _been_ obvious, for about five years -- that Edelgard is enamored with the professor. 

The odd part is… Felix’s not entirely sure if Edelgard _knows_ she’s in love with Byleth. 

Ah, but no matter, they’re climbing the stairs now, and a disgusting headache is beginning to descend upon him. Not much room to think about anything at all.

They’ve got quite a few flights to climb -- who puts an infirmary on the second floor? -- and by the time they come to the final landing, Felix is leaning pretty heavily on his professor’s shoulders. 

Byleth checks in on him with a squeeze of his waist, a silent _hanging in there?_, and Felix is too out of it to stop the blush that rises to his cheeks. He merely nods, forging onwards without complaint. 

And of course, as is his luck, who other than _Sylvain_ turns the corner.

Sylvain -- possibly the very bane of Felix's existence, someone he simultaneously trusts with his life and doesn't trust at all, heir to House Gautier, tall, strong, and handsome, someone he's practically promised his life to, someone too busy chasing women to ever look his way.

_Sylvain_, the man Felix gave up on a long time ago.

He’s got some woman hanging off of his arm, as always, and they’re chattering on as if they’re the only two people in the world. Well, that is, until Sylvain notices the two trudging down the hallway. 

“I hate to cut our conversation short, sweet thing,” he apologizes to the woman clutching his arm, “But my friends seem to be in need of some help. Duty calls!” 

The wink that the nobleman drops elicits a pleased squeal for the woman accompanying him -- and Felix hadn’t known there were still women that _trusted_ Sylvain around here --

“Professor!” Sylvain calls as a greeting, turning his full attention to them after the woman scampers off. “Don’t tell me,” he holds up a hand, dramatically searching for the answer before the two can explain. “Felix overworked himself on the training grounds. Again.” 

Byleth shakes her head, as solemn as ever. “I gave him a concussion.” 

Sylvain, damn him, finds that answer _incredibly_ entertaining. Felix can tell, because those amber eyes light up with mirth and those eyebrows raise in amused surprise. His arms cross over his chest while he waits for an explanation, and Felix finds himself lingering too long on broad shoulders and biceps. 

Felix stiffens, surprised, and shakes himself out of it.

“She caught me off guard and whacked me in the face.” He bites out, embarrassed to admit that his guard had dropped so far in the first place. “If it was just a headache, I would’ve kept training, but I can’t seem to walk in a straight line.”

Surprisingly, Sylvain sobers, the amusement leaving his expression in favor of his mouth twisting into a frown and his eyebrows following suit, knotting over his brow. He steps forwards, uncrossing his arms to reach for them, and Felix blinks in surprise when strong fingers take him by the chin and tilt his head up. 

_ Where is his anger? Where is his irritation? Where are his biting comments, his usual guard for forcing oncomers back to a respectable distance?? _

“Yeah, concussed for sure,” Sylvain agrees after he turns Felix’s face back and forth in his hands, seriously focused on whatever it is he sees in Felix’s eyes. “How hard did you hit him?” 

Now it’s _Byleth’s_ turn to blush, and Sylvain _lights up_, absolutely delighted by her reaction. 

(Felix is pretty sure that _none of them_ are used to how expressive their old professor has become. He doesn’t think he’s ever seen her blush before.)

“_Professor!_” Sylvain’s smile is sly while he pretends to admonish her for her actions. “You’ve gotta go easy on us! Especially poor, delicate Felix,” he adds, squeezing Felix’s chin once before letting him go. Felix opens his mouth to argue, but Sylvain starts speaking again before he can. “Let me help you with this sack of potatoes -- a lady shouldn’t be left to do all this manual labor by herself,” he teases while he slings Felix’s free arm over his shoulder, shooting Byleth a conspiratorial wink as if Felix isn’t standing _right there._

Sylvain is much taller than the both of them, so he has to hunch quite a bit to be actually helpful -- but he does actually take a solid bit of Felix’s weight onto his shoulders. 

“Don’t you have women to chase?” Felix groans, bordering on pleading for Sylvain to move along. “We’re nearly there, let me go,” he demands, trying to shake himself loose.

Sylvain, _damn him_, merely tightens his grip on the arm he’s slung over his shoulder and steps closer to Felix, sandwiching him in between the two people helping him to the infirmary. 

Fortunately, Sylvain's help makes the remaining trip proceed much quicker than before.

Unfortunately, it leaves Sylvain to chat with the professor while Manuela tends to Felix.

_Unfortunately_, Felix has to watch Sylvain laugh and smile and smirk and brush up against the professor, prying as many reactions out of her as he can. Sylvain is _insatiable_, and -- unfortunately for Felix -- Byleth doesn't push him away. 

That _feeling_ in his chest intensifies, tightening, squeezing, stuttering, _pounding_.

Felix used to follow Sylvain around like he held the world in his hands. 

As soon as he realized his interest in Sylvain was more than _friendly_, he shut that shit _down._

Sylvain always complains that they're not as close as they used to be, but Felix is _happy_ to keep him at arm's length as long as this _feeling_ is kept at bay. He's always known that whatever he feels for Sylvain is more than a lost cause. That's why he's put it behind him.

Plus… watching Sylvain chase every girl that crosses his path leaves a… sour taste in his mouth. 

And, judging by the way those amber eyes linger on their former professor -- in the same way everybody else's do, in the way everybody tries to hide -- Sylvain's attention has been snared on… someone else.

He should look away, should watch something other than warm amber and soft ginger, should pay attention to something that's not mint green and pink lips. He shouldn't _watch_ Sylvain flirt with their professor, he shouldn't _care_ that Sylvain's flirting with the professor, he shouldn't _want_ to be in either of their places!

"That should do it." Manuela's voice breaks into his train of thought. "Professor, come here, I'll show you the spell for this," she offers, summoning Byleth with a wave of her hand.

He's too busy fuming, staring at nothing and everything, to notice Byleth's approach. It's only after the professor's strong, lithe hands take hold of his temples, tilting his head up to face her, that Felix realizes the predicament he's in.

"Just like this, now move here," Manuela directs the path of Byleth's hands, and Felix shivers when she slides to cup his jaw. "Remember the formula I showed you, and-"

Felix feels that odd tingle, just like he'd felt when Manuela cast the spell, and the last of his headache eases. 

"Thank you, professor." He murmurs -- much softer than he'd intended to speak. 

Standing at the edge of the bed he sits on, holding his face in her hands, Byleth gazes down at him, drowning him in green. He wonders if the gentle stroking of her thumb over his cheek is a conscious movement. 

Without his permission, his hand drifts up, hooking into her elbow. 

"You'd better not go easy on me next time. This won't happen again." He insists.

Byleth smiles, and Felix's heart stutters in his chest.

He's glad he's sitting down.

"Sylvain," Byleth calls over her shoulder. "Will you walk Felix back to the training grounds?"

The momentary warmth in his chest ignites into fiery anger again. Thanks, professor.

"Why would he need to do that?" Felix demands, immediately frowning. "I'm all healed up!"

Byleth ignores him, waiting for the other man's answer.

"Sure thing, professor!" Sylvain chirps, smiling bright enough to light the room. "I'll take care of him!"

_ I’ll take care of you, I’ll take care of you, _

It’s a sentiment he can’t afford to claim. 

The heat in his chest clicks up a couple notches into rage. Comfortable, the usual, rage. 

All at once, Felix surges to his feet. "I said I'm _fine!_"

Sylvain eyes him, oddly silent. Amber eyes sweep over his figure, sending the tingling feeling scattering all the way down to his toes. 

It's only once Felix realizes how _close_ he is to Byleth, pressed chest to chest, toe to toe, that the situation registers. He's baffled by how tall he stands over her -- she always seems larger than life, there's no _way_ he can be _three inches_ taller than her,

"C'mon, Felix, let's head out." Sylvain drawls, unfazed by the outburst. "I'll even spar with you, if you want."

A gloved hand grips his arm, and, somehow, Sylvain maneuvers him out of the spot he's frozen to. 

Felix walks back to the training grounds in something like a daze. He tries his best to focus on putting one foot in front of the other instead of drowning within the pounding of his heart in his ears.

_ He's never felt hands so strong be so gentle, _

_ Warm, she was so warm, _

_And what was that_ look _in Sylvain’s eyes? It was too warm to be disdain, too sharp to be amusement,_

"Join the club, I suppose," the sound of Sylvain's voice surprises him, dragging him back to the present tense. 

Already fed up, Felix almost doesn't even humor him with a response, but he grunts out a "what?" as he forges ahead. 

Sylvain's laugh is genuine, something soft and warm instead of his usual sharp-edged snicker. "The professor. Byleth. You're in love with her."

The most irritating thing about Sylvain is that he gets these brief moments of clarity where, all of a sudden, he sees right through Felix's defenses.

Or maybe it’s _not_ all of a sudden. Maybe Sylvain can _always_ see through him. 

He doesn’t like the thought of that.

Felix's lip curls in a snarl before he answers. "Don't be stupid. I am no such thing."

"I forgot how stubborn you are," Sylvain sighs, shaking his head -- as if it’s an _easy_ thing to forget! "Fine, attracted, at least?"

Felix snorts and rolls his eyes, denying the accusation. Dangerously close to being exposed, his only choice now is to lie to Sylvain's face and hope he doesn't catch it.

"To what? She looks like she's been dipped in frosting with her hair like that." He keeps his tone as flat as possible, as _uninterested_ as possible. When Sylvain shakes his head in amusement, Felix panics, lashing out in a last-ditch effort to derail the conversation before he's figured out. "What, Sylvain, you expected me to gush about her breasts? Or her legs? I'm not a _pig_ like you."

"Hey, hey, I didn't expect you to answer like me at all!" the redhead complains, raising his hands in surrender. He looks genuinely upset by the accusation, but Felix stands by his word. "I _know_ you're a different person, Felix. Of course different things are gonna catch your eye. I just wondered what your preference was."

The more Sylvain looks like a kicked puppy, the worse Felix feels about his outburst. 

But that won't stop him from deflecting the question at hand.

"I don't have a preference." Felix settles on answering with a lie. "I'd rather train." He follows it up with a half-lie and hopes Sylvain doesn't notice.

"Really?" Sylvain sounds surprised, from what Felix can hear of his voice while walking ahead of the taller man.

A hand grips his shoulder and spins him on his heel, and while Felix is scrambling to orient himself, he trips on something. Knocked completely off balance, Felix is completely at the mercy of the grip on his shoulder when it pushes him backwards.

Luckily, he lands against a wall, and his hands slap -- one, two -- against the wall as he catches himself. 

A third hand smacks the wall, right next to his ear, and suddenly Sylvain is towering over him. A smug smirk is beginning to pull at the redhead's lips, and it occurs to Felix all at once -- did Sylvain just _kabedon_ him?

Honestly, he's too used to Sylvain's shenanigans to push him away or struggle -- and, unfortunately, Sylvain is stronger than him (just by merit of the kind of weapon they each wield), so even if he _did_ try to slip away, his efforts would be for naught.

Even so... what with the way he's gazing down at Felix, auburn eyelashes framing a look that's absolutely _predatory..._

"You can really look me in the eye and tell me you don't get a _little_ hot under the collar while you watch her fight?" Sylvain purrs, head tilted to the side while he watches Felix intently for reactions. "Not even when you think about her skill with a sword? With combat? With strategy?" He continues to bombard Felix with questions, waiting for one to snag.

Felix refuses to give him the satisfaction.

"You don't anticipate the days that she asks you to spar? You don't get excited when she lands a hit?" Sylvain brushes his knuckles across Felix's cheek, where the professor had smacked him. "You don't like it when she praises you? You don't like it when she scolds you?" He murmurs, leaning closer closer closer until hot breath washed over the shorter man's face. "I just wanna know, Fee,"

_ Don't look at his mouth, don't look at his mouth, _

_ Look at his hair instead, the gentle sweep of auburn waves -- bet they're so soft, bet if you knotted your fingers up in them and pulled, he'd -- _

_ Oh shit. Oh. Shit. Not this again, not again, not while he's hung up on the professor as well, please no, goddess, no, _

"Don't get your hopes up." Felix dismisses him -- but his voice is shaking, and his shoulders are much too tense. "You're out of your mind."

He pushes past the man towering over him, fingers clenched into fists so Sylvain won't see them trembling. 

The weight of amber eyes rests on his back until Felix disappears behind the doors to the training grounds.

This _feeling_ in his chest, the stuttering of his heart, the tension in his body, in his shoulders, in his abdomen, in his thighs--

_ He's hard he's hard he's so hard _

_Damn_ Sylvain for doing this to him, _damn him!_

The rage he'd been searching for floods back into him all at once, and he storms over to the rack of training weapons in a furious storm.

Five years ago, he could've squashed all of this down and moved on with his life.

But this… this is not going away.


	2. Sylvain

**Notes for the Chapter:**

> okay so i'm planning to make this a series of one/two-shots!! It doesn't end here!

There's something about this odd feeling in his chest that Sylvain can't shake. 

He's used to fleeting feelings, to momentary attraction, to passing interest. The fluttering in his chest usually means that a woman has caught his eye -- preferably someone who hasn't caught on to his reputation yet. But a feeling that lingers, a feeling that _lasts_…

Maybe it's because they're at war. Maybe it's because it's been five years since he's seen anyone from the academy. Now, gathered back in Garreg Mach, it's oddly thrilling to see how everyone has filled out and matured, to see how different everyone is after the years took their toll.

Whatever it is, it sticks with him, following him around like rumors after a bad breakup. 

Usually, he ignores it. Worrying about it won’t get him anywhere.

\---

He thinks it began when Byleth disappeared. Maybe the feeling -- whatever it is -- was building beforehand, but _that day_ was what started everything.

That day hurt Sylvain more than he’s willing to admit. It nearly broke him. 

Sylvain isn’t used to depending on people. He knows, whether by their own faults or his own, that nobody will _always_ be there for you. 

Not Ingrid, not Dimitri, not even Felix. 

But Byleth… Byleth was a constant in his life. She always encouraged and supported him, no matter how reckless he was, no matter how lazy he was being. She always took him at face value every time she saw him, unmoved by the latest rumors floating around the monastery, unfazed by the overwhelming amount of times she’d seen him at his worst, at his most vulnerable. 

And he’d lost her. 

For five years, he’d been convinced that he’d lost her.

For five years, he’d grieved in silence, packed his hurt away where no one could see it, tried to move on with his life. 

Until the Millenium Festival -- or, well, what would’ve been the Millenium Festival if the whole goddamn _continent_ wasn’t at war. Until the Millenium Festival, there had been no word of Byleth for _five years. _And then, there she was. 

And then, there they _all_ were, back in the ruins of Garreg Mach -- as if The Empire hadn’t denounced Edelgard, as if Edelgard hadn’t told them an underground society of mages has been controlling Fodlan for the past who knows how long.

It was all _weird._

Walking around the halls of his old school felt like reliving a dream. Greeting people with a smile and a laugh felt like he’d died and this was heaven. Or eternal punishment. He wasn’t sure which. 

But the dream state couldn’t last forever. 

When he’d finally crossed paths with Byleth, something within him cracked.

He’d smiled and he’d laughed like he did with everyone else, greeting his old professor as if nothing had ever happened. As if she hadn't disappeared for five years.

But that _feeling_, that _ache_ that he’d locked behind every defense he had, started to seep through again. By the time she moved on, called upon by another former student, his hands were shaking. 

He’s been here before. 

Once, a long time ago, he’d locked up all his feelings, promised he’d never feel like that again,

_ Ink black hair, vermillion eyes, _

_ A little hand fisted in his shirt, following him everywhere, promising him forever, _

_ “He’s dead, and they called him a _hero_,” _

and it’s been working so far. He thinks he’s numb to that ache now. 

But, unlike last time, he doesn’t get the chance to properly patch the crack before it’s weathered again.

Byleth _knocks on his door_ the night after they first run into each other. When Sylvain answers the summons, he stares down at his professor in shocked silence for just a beat too long. 

“Professor! What brings you here?” He yanks the facade back on, scrambling to cover. “Looking for a midnight rendezv-”

“Sylvain,” 

_ouch_, 

_ Professor, be careful, _

“I came to check on you.” She informs him, as neutral as ever. “You seem…”

She trails off, green eyes flicking from his head to his toes. She never does finish her sentence. 

“I’m fine, professor,” he assures her. Such a simple statement shouldn’t be such a big lie, but it is. “Care to come in? It’s cold out, tonight.” 

Byleth scans him again, looks beyond him into his room, and nods.

She closes the door behind them while Sylvain scurries to pull out a couple chairs, setting up a place to sit and… chat.

Oh goddess, they’re going to _talk_. Byleth is going to drag it out of him, and he’s going to-

“It seems most everybody has cut ties with their families, or is in the process of,” Byleth begins, making small talk like a champ.

Sylvain can’t take it anymore, he’s going to combust.

“Where _were_ you?” The accusation rips out of him, all in a rush. “What happened? Why- why didn’t you-”

He shuts his mouth as soon as his voice starts to warble, but Byleth is too keen to miss such an obvious tell. Green eyes are on him in an instant, and she’s looking at him like she _knows_, already.

“You didn’t hear?” She hums, surprised. Sylvain merely shakes his head, forgoing admitting that he’s been pretty out of it so far. “I was asleep.”

At that, all he can do is put his head in his hands. “Right.” He sighs, watching colors burst in the black when he presses his palms into his eyes. _Of course she’s going to be vague about it._

“I almost didn’t wake up.” She adds- and there’s something about the way her eyebrows pull together that makes Sylvain thinks she’s _serious_. “If it weren’t for… I…” she trails off, staring off at nothing. 

She looks as lost as he feels. 

Sylvain can’t stop himself from reaching out and taking her hand in both of his. It’s part habit, part _need_, and he’s too tired to fight the knee-jerk urge. 

“I’m glad you’re back, professor.” He murmurs, and a genuine smile slips out alongside it. He knows it’s genuine because he feels _tired_, and his usual smiles are bright and full of energy. “I was really worried.”

Is it wrong to feel blessed when her fingers twist into his?

He stares at their entwined hands for a moment, warring against the defenses that threaten to crack, that threaten to let that _feeling_ come spilling back out. 

“You thought I was dead,” Byleth notes, stating the observation as if it’s established fact. Sylvain chokes on his next breath, the cracks in his walls widening. 

A call of his name has his gaze swinging up to meet hers, and he realizes he’s got a death grip on her hand. 

“I’m sorry.” She says, soft and simple. “I didn’t intend to leave you.” 

When the apology leaves her lips, something within him _shatters_. 

He spends the better part of the next hour on his knees, sobbing into her lap. 

Byleth doesn’t say a word, just strokes through his hair and rubs wide, soothing circles into his back. She shushes him when he apologizes and she shushes him when he thanks her, so he just shuts up and cries.

It’s the first time he’s cried -- _really_ cried -- in… in _years_. Maybe since Glenn died. 

And oh goddess, thinking of Glenn only makes him think of Felix, and thinking about Felix is _really_ not helping him calm down right now, and--

“You’re not alone, Sylvain,” Byleth whispers into the air between them. “Even without me -- you know that, right?” 

Sylvain can only shake his head. He can’t voice what he knows -- that he’s made too many mistakes. His friends may be knights, but he’s beyond saving. 

They sit in silence for a moment more -- maybe an hour, Sylvain can’t tell -- until his professor speaks up again. 

“I used to feel like I couldn’t trust anyone,” Byleth murmurs. Soft. Vulnerable.

The confession has Sylvain sitting up, tilting his head back to look up at her. It surprises him, because she _never_ brings up her past, and rarely answers questions about it. 

“My father said that, when you decide to trust people and get burned, you either move on or shut yourself off forever.” She continued. Her hand slid from his hair to his shoulders, and though she looked down at him, he could tell she was looking through him, beyond him. “I was pretty close to shutting myself off forever. He didn’t want that for me.”

Sylvain lets out a breath through his nose. Clears his throat. Tests his voice. “Your dad cared a lot about you.”

Green eyes focus back in on him. Strong hands squeeze his shoulders. “Sylvain,”

“Yeah?”

Byleth is quiet for a moment, long enough for Sylvain to plop back into her lap. She slides her fingers into his hair again.

“I don’t want you to shut yourself off forever.”

Apparently, Sylvain is not done crying.

\---

Somehow, that encounter knocks him out of the orbit he’d been stuck in. Clears his head a bit.

Unfortunately, what with the absolute annihilation of the defenses he’d been building up for the past five years, everything is a little _too_ clear. 

He’s in love with Byleth. He’s in love with Byleth because if Byleth loved him back, it wouldn’t be for his house name or his Crest. 

It’d be because she loves _him_. 

He _knows_ all that, already, but he hasn't really come to terms with it until now. Hasn't accepted exactly how far in he really was. 

Part of the reason why he’s been putting off accepting it is because… Byleth doesn’t love him like that.

The other part is… well, because of how many _other_ people are in love with Byleth. 

Other, much more worthy people. Smarter people. Stronger people. 

Sylvain is _far_ out of his league, here. 

That gives him a little hope. If the professor and everyone else can see how far out of his league he is, then they won’t take his usual flirting seriously. Oh, silly Sylvain, wasting sweet words on the professor. 

As long as they don’t suspect he actually _means_ them… he should be fine. 

And, of course, what better to sell the act than a beautiful woman on his arm who stares adoringly up into his eyes while he shows her the progress they’re making rebuilding the monastery? Sylvain couldn’t _possibly_ mean a word he says if he’s always carting a new woman around. 

Of course not. 

“What’s down this hall?” The woman on his arm wonders, staring adoringly up into his eyes while he shows her the progress they’re making rebuilding the monastery. 

Sylvain smiles. “Well, behind _that_ door is the stairs back to the first floor. I didn’t think you’d want to end our tour so soon…?”

The woman gasps and quickly backtracks. “No, no, I-”

“I was just teasing, lovely, no need to-” As they turn the corner, moving along, Sylvain pauses mid-sentence. The door to the stairs swinging open snagged his attention, but the tangle of bodies shuffling into the hallway kept it. 

Mint green hair -- it’s Byleth. 

And clinging to her, leaning heavily on her shoulders, face flushed the most _delectable_ red -- Felix. 

He watches the professor try to take a step forward, nudging Felix along, but the swordsman only stumbles alongside her in a clumsy attempt at walking.

“Ah.” Sylvain hums, mostly to himself. “I hate to cut our conversation short, sweet thing,” he apologizes, bowing low to the woman he’s accompanying. “Duty calls.” 

Luckily, she understands the situation at hand -- sending Felix a pitying glance that would’ve had the swordsman _snarling_ at her, had he seen it -- and scampers off down the very stairs they’d just discussed. 

“Don’t tell me,” Sylvain declares as he approaches the two, pausing solely for dramatic effect -- and because he knows it will piss Felix off. “Felix overworked himself on the training grounds. Again.” 

Byleth, in her usual stoic honesty, shakes her head and announces that she may have concussed Felix. 

Felix Hugo Fraldarius. Concussed him.

This is. Wonderful. This is _hilarious_. 

He is _desperately_ holding back his laughter, hoping the way his lips keep trying to twitch into a smile won’t give him away while he waits for an explanation. Luckily, Felix won’t look him in the eye -- but that’s nothing new.

(Not that he can get away with things just because Felix won’t look him in the eye. There are other facial tells to emotion, and Felix is a near master at decoding them.)

He revels in Felix’s embarrassment, glad to see the skillful swordsman taken down a peg or two... all up until Felix admits he can’t walk in a straight line. 

Sylvain doesn’t know a lot about injuries (that’s more of a white magic thing, not his style), but he knows enough to know that’s kinda serious. 

And yeah, it’s kinda odd that Felix lets him grab his chin and turn his face this way and that, but it’s _weirder_ that his pupils aren’t dilating and constricting, that garnet eyes are having a hard time keeping up with the movement even though Sylvain hasn’t moved an inch.

He tries not to focus on how warm Felix is under his fingers, tries to ignore the rush of satisfaction it gives him to have the swordsman pliant in his hands. His jawline is strong and sharp, absolutely _regal_, and Sylvain finds himself tracing the curve of his bottom lip with his thumb before he can stop himself.

_ Fuck. _

He turns his attention to the professor before he can get too swept up (_in old feelings, feelings he’s long buried by now… right?_) and, luckily, Byleth gives him something to work with right off the bat. She looks away, cheeks burning with sheepishness. The sight makes him smile before he can catch it.

All sorts of responses bubble up on his tongue -- ranging from “things that will piss Felix off” to “things that might make the professor blush _more_” -- but he reigns himself in, settling for something in the middle of both.

“Professor!” He chastises with a click of his tongue -- which should be the first sign that he’s not serious, since he’s in _ no _ position to be reprimanding someone who’s technically his superior. “You’ve got to go easy on us! Especially poor, _delicate_ Felix,” he makes sure to tack another falsehood onto the end, just to make his point.

He really can’t resist teasing the shorter man, especially when his face scrunches up like that, silently protesting Sylvain’s choice of description. Felix’s reactions are always a nice change of pace from stony-faced Byleth -- who doesn’t even crack a smile when he winks at her after offering his help.

Slinging Felix’s arm over his shoulder is easy.

So is stepping closer to him, pressing up against his side.

Too easy. 

For a moment, walking down the final stretch of hallway before the infirmary’s doors, they’re a unit, walking in unison, fit perfectly together like puzzle pieces.

It’s too easy.

Felix, warm against his side (blushing, is he _blushing?_), a calloused hand hanging loosely over Sylvain’s shoulder (for once, it’s not clenched), Sylvain’s own hand spread wide over the expanse of his ribs (he’s just holding him up, just steadying him, that’s all)... Byleth, as steady as always (a pillar they can always lean on), her arm crossed over Felix’s back so her hand can grip his waist (her knuckles bump Sylvain’s thigh as he walks), her heels clicking against the tiles in time with their own footsteps (oh how he listens in vain for that sound to approach his room once more)... 

It’s like a dream. It all goes so smoothly. It can’t be real.

It’s too easy. 

When they disband, depositing Felix into Manuela’s care, Sylvain feels that… _feeling_. Again.

All the longing, all the regret, all the pain, he… He thought he’d gotten rid of it, thought he’d cried it all out. 

“Something on your mind, Sylvain?”

Sylvain tears his eyes off of the concussed swordsman across the room. When he turns to Byleth, he tries not to wince away at the knowing look in her eyes.

“Actually, I’m glad you asked!” He chirps, scooting closer to her, beaming at her with his brightest smile. “I was just thinking, this is the closest we’ve been in a while and -- I think, personally -- we should spend some more time together.” He delivers the line with his best Suave Look, and a hand on her knee for good measure. 

Byleth smiles, something small and amused. 

_ Bingo_.

“You should’ve just said so,” she hums -- and her voice is so flat, he can’t tell if she’s teasing him or not. “We should have tea together soon. Sit down and talk.” 

Sylvain readily agrees, always willing to steal the professor’s precious free time for himself. 

Her smile lasts for a moment beyond his assent, but it falls when her gaze slides back to Felix. 

“You know Felix well, don’t you, Sylvain?” 

The question catches him off guard. He tries not to choke while he swallows it. 

“Sure, professor. We grew up together, remember?” He smiles, covering the insistent _pang_ in his chest with glib geniality. 

_ Eyes of vermillion wonder, eyes that looked up at him like he held the world in his hands, _

_ Back then, he did hold the world in his hands, but back then, the world had vermillion eyes. _

_Sylvain's hands are empty now, and he’s not sure what he did to empty them. _

Byleth looks between the lanceman and the swordsman, her gaze as discerning as ever. But whatever she sees between them, she doesn’t comment on it.

“Felix is acting… strange.” Their professor decides, eyes narrowing the slightest bit while she watches Manuela heal her student. “Something is off. I can’t…” her eyebrows furrow, something like determination flashing across her features for a moment. “I don’t know how to help.” 

This is… not what Sylvain was expecting his professor to ask of him. 

“I can’t think of anything off of the top of my head,” he admits, honestly at a loss, “But I’ll keep an eye out, if you’d like.” 

Byleth nods, short and decisive. “Thank you, Sylvain.” 

He doesn’t notice her hand over top of his (where it still rests on her knee) until she squeezes.

That feeling bubbles up again, but there are no walls left to hide behind. 

All he can do is endure it. 

Manuela calls Byleth over, gesturing towards Felix and offering some white magic training, so Sylvain tunes out for the time being. With a long yawn and a big stretch, he leans back to lounge in his seat.

With two of the most interesting people (at least to him) in the room, it’s no surprise where his wandering eyes land. 

Byleth’s hands are so small, but they cup Felix’s face _just_ right. 

(Sylvain wonders if anyone’s _ever_ held Felix so gently. Now’s not the time to think back on all the times he should’ve been the one to do it.)

Head tilted back, putty in her hands, Felix all but stares up at the woman towering over him. Sylvain watches his lips part, watches his tongue run over his lip, watches his hand swing up and hook into her arm to keep her there, close to him,

and

All of a sudden, Sylvain knows what’s wrong with Felix.

It’s ever more obvious with every passing second -- what with how low the swordsman’s voice drops when he finally speaks up, or the pink that tints his cheeks when the professor smiles down at him. 

All of a sudden, Sylvain remembers just how far out of his league he is. 

"Sylvain," Byleth calls over her shoulder. "Will you walk Felix back to the training grounds?"

While Felix protests, Sylvain catches Byleth’s eyes. 

_Something is off. I don’t know how to help._

His professor is worried about Felix. If Sylvain can do something to help, well… Duty calls.

“Sure thing, professor!" Sylvain chirps, donning his brightest smile. "I'll take care of him!"

_ I’ll take care of him for you, for you, professor, because I can’t have him for myself. _

Of course, being passed off from caretaker to caretaker doesn’t please Felix, and he rushes to stand on his own two feet. His pretty face is already twisted with discontent while he demands independence, towering over their professor.

“I said I’m _fine!_”

The shout echoes in the quiet infirmary. The shout surprises Sylvain.

It’s unlike Felix to yell.

Brood and mutter under his breath, sure. Lash out with razor-tipped insults, sure. Make some kind of face and walk away, sure. 

Maybe the professor’s right. Maybe there _is_ something wrong with Felix. 

But, in the next beat, Felix switches tracks, face going from all scrunched up and upset to slack with surprise, hands that were fisted at his sides uncurling, lifting to hover over Byleth’s hips as if he means to hold her there. 

It should not be so _goddamn_ _interesting_ to notice how the two fit together, chest to chest, toe to toe, close enough to lean forward and --

"C'mon, Felix, let's head out." Sylvain keeps his tone as neutral as possible while he takes hold of the swordsman’s arm. "I'll even spar with you, if you want."

Anything to get them out of there.

Anything to push down the feeling in his chest.

_Anything_ to escape the tightening of his pants.

Felix doesn’t even fight him. He looks lost while Sylvain drags him out of the infirmary, barely notices the stairs while Sylvain guides him towards the training grounds. 

Byleth is _right_. This Felix is a Felix Sylvain doesn’t know. This is a Felix that Sylvain wants to figure out.

“Join the club, I suppose.” Sylvain finally speaks up, breaking their silence. 

As soon as Sylvain speaks, Felix pushes ahead, leaving him behind with a weary sigh of “What kind of nonsense are you spitting now?”

Ah. Jackpot.

It’s cute that Felix thinks Sylvain will be so easily swayed.

“The professor. Byleth. You're in love with her." The professor’s name feels foreign in his mouth, but he tries again, walking faster. (It’s not hard to catch up when Felix stands five inches shorter than him.)

Felix’s lip curls in a snarl. Sylvain’s heart stutters in place. 

"Don't be stupid.” The shorter man bites out. “I am no such thing."

"I forgot how stubborn you are," Sylvain can’t help but sigh. Felix is a lost cause. "Fine, attracted, at least?"

Felix, that stubborn man, denies again. To prove his point, he makes sure to insult not only Byleth but Sylvain as well, doing what Felix does best when someone peers too deeply into his soul. 

And, for the record, _Sylvain_ thinks their professor’s mint frosting hair is cute. 

Though, “a pig like you” rings a little too harshly in his ears. He’d thought by now Felix would _catch on_, but… it seems Sylvain is _too_ convincing.

“Hey, hey, I didn't expect you to answer like me at all!” Sylvain raises his hands in surrender, showing Felix he means no harm. "I _know_ you're a different person, Felix. Of course different things are gonna catch your eye. I just wondered what your preference was."

And it’s true! Sylvain’s never seen Felix express interest in _any_ kind of human beyond what they could offer him in improving his skills. And now, all of a sudden, it’s _Byleth_. 

_ Why? What about her? When? _

"I don't have a preference. I'd rather train." The swordsman keeps his answers as sharp as his blade, doing his best to cut Sylvain off before he can dig any deeper. 

But Sylvain won’t let him slip away. Not this time. 

It’s rare to catch Felix off guard, but he’s quite certain the shorter man is too lost in thought to be vigilant right now -- which proves correct when he successfully manages to push Felix up against a wall. 

(It’s a move he’s attempted on many women with mixed results. Judging by the way Felix’s eyes are wide enough to swallow the moon, mouth hung just the slightest bit agape in pure surprise, Sylvain thinks he’s succeeded with this attempt.)

"You can really look me in the eye and tell me you don't get a little hot under the collar when you watch her fight?" Sylvain purrs, low and smooth, head tilted to the side while he watches Felix intently for reactions. "Not even when you think about her skill with a sword? With combat? With strategy?" 

Felix schools his expression into something carefully neutral, eyes fixed somewhere just beyond Sylvain’s shoulder.

Sylvain will not back down without a fight.

"You don't anticipate the days that she asks you to spar? You don't get excited when she lands a hit?" He dares to brush his knuckles across Felix's cheek, grazing over pale skin that’s beginning to flush pink. "I just wanna know, Fee," he murmurs -- and he doesn’t notice how close he’s leaned in until the heat of his own breath warms his cheeks, radiating off of Felix’s skin. 

_ Don’t look at his mouth, don’t look at his mouth, _

_ Don’t think about how soft his lips would feel, pressed against yours, don’t think about how you know his neck is ticklish, don’t think about wrapping your arms around his waist, _

_ Oh shit. Oh. Shit. Not this again, not again, not while he's hung up on the professor as well, please no, goddess, no, _

"Don't get your hopes up."

Sylvain almost thinks the goddess herself is speaking to him, shaking her head at his foolishness, until he registers the wobble in Felix’s lip.

“You're out of your mind." The swordsman dismisses him with a scoff, slipping out from underneath him without even a glance in Sylvain’s direction. 

But Sylvain saw the flush of his skin, the fiery red of his face. Felix’s fists are clenched as he storms away, but Sylvain wonders… if he unfolded them, would they be shaking?

Sylvain's are. 

That _feeling_ thuds against his ribcage, demanding to be freed. 

This… this is not going away.

**Notes for the Chapter:**

> I finally married both my boys a couple night ago and lemme tell you... First of all, they jipped us on Sylvain, but whatever, at least I married him. Second, WOW Felix WOW THANK YOU FOR BLESSING ME,, ,

**Author's Note:**

> Next chapter: Sylvain!!


End file.
